1. Field of the Invention
The present invention relates to a disc driving apparatus, which is used for reproducing audio data recorded on a disc (a disc-shaped recording medium) and to recording desired data on a disc. In particular, the present invention relates to a mechanism to clamp a disc while reproducing and recording and to a disc driving apparatus that includes the same mechanism.
2. Description of the Related Art
Generally, a disc driving apparatus, such as a CD player or a DVD player, includes a turntable that holds and rotates a disc, an optical pickup that moves in a radial direction along the surface of a disc, a disc-clamping mechanism that clamps the disc so as to make the disc synchronously rotated with the turntable, and so on.
One of the known disc-clamping mechanism is as follows. The disc-clamping mechanism includes a clamping plate (clamper) rotatably sandwiching a disc by cooperating with a turntable, and a clamp base (clamp arm) whose one end is used as a fulcrum so as to pivot in an up and down direction, wherein a clamper holder made from a metal plate and so on is screwed and fixed on the clamp base so as to rotatably hold the clamping plate by the clamp holder and the clamp base (for example, refer to Patent document 1: Japanese Utility Model Patent Application Publication No. hei6-4945, paragraphs 0003 to 0007, FIG. 3 and FIG. 4).
In addition, a structure having a square hole on a clamp base, whose outer-edge works as elastic element to set a clamping plate on the clamp base, a clamping plate which has two disc-shaped flanges, and the clamp base which rotatably holds the clamping plate is known as a disc-clamping structure (for example, refer to Patent document 2: Japanese Patent Application Publication No. hei7-272371, paragraph 0030 and FIG. 13).
Nevertheless, the structure described in Patent document 1, which has a clamping plate rotatably held by a clamp base and a separately formed clamper holder screwed on it, has the following problems. One is high cost and increase in the number of parts because a clamper holder and screws are needed to screw a clamper holder on a clamp base. Another problem is an increase of the number of processes when assembling a clamping plate, which inhibits productivity.
In addition, according to Patent document 1, rattle is prevented when a disc-clamping by a clamping plate is released since the clamping plate contacts a part of a chassis. However, a concerns that rattle noise occurs due to shaking of the clamping plate in the diameter direction under the environment of vibrations, such as in-car use, because a motion of the clamping plate is limited only in the axial direction according to Patent document 1.
According to the supporting structure of Patent document 2, the number of parts can be reduced. However, it is a difficult to make a support member from a metal material that is rigid because the outer-edge of the square hole is required for the part to have elasticity. Another problem is that rattle noise easily occurs because a clamping plate set in a square hole can move in the diameter direction (i.e. plane of the plate) and axial direction (i.e. vertical of the plate) of a clamping plate when in an unclamped state.